This invention is concerned with composites in which a glass or glass-ceramic matrix is reinforced with carbon fibers embodied therein. It is particularly concerned with such composites wherein the carbon fiber is provided with a metal coating.
Composites, in which ceramic matrices, particularly glass, are provided with carbon or silicon carbide fibers, are described in some detail in the literature. For example, graphite-glass combinations are disclosed in U.S. Pat. Nos. 3,607,608, 3,681,187; 4,256,378; 4,263,367 and 4,265,968. A variety of different glasses is shown, but one, a borosilicate available from Corning Glass Works under Code 7740, is frequently referred to as exemplary.
A basic purpose of fiber reinforcement is improvement of mechanical strength. This is often referred to as bending strength. One of the standard tests involves a three point bend apparatus. The measured data is then converted into, and reported as, modulus of rupture (MOR) in thousands of pounds per square inch (ksi).